Imaging-compatible oral retractor system for use in image-guided transoral robotic surgery

Currently-available metallic retractors typically used in transoral robotic surgery (TORS) cause significant artifacts in CT imaging and cannot be safely used in MRI. The lack of imaging-compatible oral retractors poses a significant challenge to enabling intraoperative imaging in TORS. This work introduces a customizable compact 3D-printed polymer retractor system that enables multiple modes of adjustability, artifact-free CT and MR images, and adequate surgical exposure. The polymer retractor design was modeled after the traditional metal FK and Crowe-Davis retractors and can be used with an acrylic suspension system that rests over the patient's chest. Finite element analysis was conducted to evaluate the mechanical performance in relevant clinical loading conditions. Cadaver experiments followed by endoscopic, CT, and MR imaging were performed to demonstrate functionality. Artifact-free CT and MR images were obtained. An inter-incisive distance of 42.50 mm and 200.09 cm(3) working volume were achieved, which allow the introduction of robotic arms and necessary instruments in TORS. This polymer retractor system makes it possible to acquire intraoperative images and establishes a critical step to make image-guided TORS both feasible and effective.